Vintage Port refers to a wood aged,
single-quinta port, made from the unblended grapes of a single
estate in a single
vintage.
Production
The Douro valley in Portugal is an extremely hostile place to grow grapes, but the various port houses have been doing just this for several centuries. The climate and rainfall vary widely from year to year, greatly impacting the quantity and quality of grapes being grown in the valley. Twice or three times every decade, the climatic conditions of a particular year are good enough to yield a suitable quality of grapes. These young wines are fermented in the traditional fashion of port wine, and then allowed to age for two years in oak barrels. The resulting port is then tested and if it is deemed to be of suitable vintage quality, that year is "declared" to be a vintage year, and vintage port wines are then bottled, unfiltered, from this two-year old stock.
There are guidelines in Portugal about what may and may not be sold as vintage port, and this keeps the quality level high. You will not find a specific year of a port wine on the bottle except in these very special years that a vintage port is declared. You can expect that these wines will represent the highest echelon of all ports you will ever taste.
Non-vintage year wines are used to produce other things such as reserve-quality ports, tawny ports, and so on.
Storage and Maturation
A vintage port will continue to age for many years while still in the bottle. To this end, it is best to store the bottle in a wine cellar or appropriate container, at around 55 degrees Fahrenheit. Store the bottle horizontally, so that the cork is always in contact with the wine. Over the next fifteen or twenty years, the character of the port will change, and its overall quality can improve many times. Do not even think of opening a vintage port for at least ten years after it was bottled, to do so is sacrilege of the highest order.
Serving
During the aging process, the unfilitered port wine will throw a deposit or sediment in the bottle. To remove this, it is best to decant the port before it is served. Allow the bottle to stand for an hour or so to allow the particles settle to the bottom, and then slowly pour the port into the decanter. When you are near the bottom of the bottle, a strainer or filter can be used to prevent the sediment from getting out. Getting sediment in your glass will be like drinking coffee grounds. Not good.
Use a real port glass to serve the wine, such as a Riedel port glass. These glasses are shaped to allow swirling of the wine, and the fragrance of the wine to fill the glass and reach your nose. Besides, if you're drinking a $200 bottle of port , shouldn't you at least drink it out of nice glassware?